[vsnet-alert 1437] CVC 160 (VW CrB, T Leo)

[Tonny Vanmunster <tvanmuns@innet.be>]

BELGIAN ASTRONOMICAL SOCIETY V.V.S. -  Working Group Variable Stars
Cataclysmic Variables Circular No.160              1998, January 26
Ed.: T. Vanmunster, Walhostraat 1A, 3401 Landen, BELGIUM
     Internet: tvanmuns@innet.be                  TEL. 32-11-831504
     CVC Web Page : http://vsnet.astro.columbia.edu/~cba/cvc
===================================================================

VW CrB [UGSU, 14.5 - <17.5p]
============================

Tonny Vanmunster, CBA Belgium Observatory, reports his detection
by CCD of an outburst of VW CrB (alias Var21 CrB), using a 0.25-m
telescope and ST-7 CCD camera (unfiltered exposure). Observation :

1998 Jan 26.132 UT, 15.8 (T. Vanmunster, 0.25-m SCT, unfilt. exp.);

Apparently, the object has not been observed in recent weeks [VSNET
reports], so it is difficult to judge in which state of the outburst
the system is residing. Follow-up observations therefore are
encouraged.

During the May 1997 outburst of VW CrB, superoutbursts were indepen-
dently detected by Rudolf Novak, Nicholas Copernicus Observatory,
Brno, Czech Republic and by the undersigned [CVC 139]. A superhump
period of 0.0743 +/- 0.0006 days was subsequently derived by D.
Nogami et al., Kyoto University, Japan.



T Leo [UGSU, 10B - 15.7B]
=========================

Gene Hanson, Arizona reports his visual detection of an outburst
of this SU UMa-type dwarf nova. Confirmation has been received from
Gary Poyner, UK. Observations :

1998 Jan 25.088 UT, [15.3  (G. Poyner, visual);
     Jan 25.460 UT,  13.9  (G. Hanson, visual);
     Jan 26.105 UT,  10.4  (G. Poyner);
     Jan 26.404 UT,  10.7  (G. Hanson);

T Leo was last seen in outburst in October 1997 by P. Schmeer. This
was a normal outburst (only 2 positive observations).

T Leo is a remarkable object, in the sense that on a couple of
occasions, it has shown rebrightenings after outbursts (maybe
of a similar nature as the ones exhibited by GO Com, V1028 Cyg
and others). These secondary maxima of T Leo can be almost as bright 
as the primary outburst, but last for only one day or so.

Since there is considerable interest in a detailed study of this 
phenomenon, T Leo has been added to the CVAP programme in May 1995.
Our primary objective was to monitor a number of future outbursts 
intensively in order to detect and follow-up these secondary
maxima.

We encourage our observers to continue monitoring this object
during its present outburst in the period after the initial decline.


Tonny Vanmunster

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